Lack of error message when a variable is annotated with Final without explicit type. #990
Description
Reproducible steps:
$ git clone https://github.com/psf/black
$ cd black
$ git checkout a552f7096a9f6e016c9bb1df1e0a77a17caeec1c
$ pip install -e .[d]
$ cd src/
$ mypyc blib2to3/
It fails with the following error message:
Traceback (most recent call last):
File "mypyc/irbuild/builder.py", line 247, in accept
File "mypy/nodes.py", line 1793, in accept
File "mypyc/irbuild/visitor.py", line 251, in visit_name_expr
File "mypyc/irbuild/expression.py", line 130, in transform_name_expr
File "mypyc/irbuild/builder.py", line 992, in emit_load_final
File "mypyc/irbuild/builder.py", line 540, in load_final_static
blib2to3/pgen2/tokenize.py:559: AssertionError:
The line in question from Black is https://github.com/psf/black/blob/a552f7096a9f6e016c9bb1df1e0a77a17caeec1c/src/blib2to3/pgen2/tokenize.py#L559
numchars was declared earlier as:
numchars: Final = "0123456789"Changing it to
numchars: Final[str] = "0123456789"would make mypyc succeed.
But the original error message is hard to understand.
This is a new issue since mypy 1.0.0, Black is currently using 0.991.